Oscilloscope Lessons...

[Fisherdude]

The clips/probe doesn't matter, reversing it will turn the signal upside down and with a sine wave that is not worth worrying about...

I'm afraid I don't understand what you're trying to say, but given that the OP is a beginner I have to strongly suggest that he not pay attention to your post since your post is incorrect. Reversing the probe connections will do far more than simply "turning the sine wave upside down". Following your statement can cause catastrophic damage to equipment connected to an oscilloscope.

The proper use of the probe and ground clip does matter, and in fact failing to understand circuit grounds and earth grounds and how an oscilloscope works with grounds is probably the single most serious mistake a beginner can make, along with connecting to a voltage source higher than the scope can handle.

If you have a scope probe connected properly, with the ground clip connected to circuit ground and the main probe connected to the point in the circuit where you wish to measure a voltage and/or observe a waveform, and then you reverse the connections, you will take the point in the circuit where you were taking measurements and make a dead short connection from that point to ground, possibly destroying multiple components in the process.

To Steelman:

First, congrats on wanting to learn new things!! This electronics stuff really is fascinating, and you will find it increasingly interesting the deeper you get into it. Unfortunately, as you're already finding out, learning it all by yourself can be both frustrating as well as compelling. I would strongly urge you to take another look at your local community/junior college Electronics Technology offerings. No, you won't find a course on "Using an Oscilloscope", any more than you will find a class on "Using a Socket Wrench" listed under Automotive Technology. You'll learn how to use the tools when you take a class on how to work on engines. If you take an Introduction to Electronics course, then the next two classes you would normally take are DC Circuits and AC circuits. In those classes, particularly AC Circuits, you'll get to play with scopes for hours on end, and you'll learn a lot. Nothing beats hands-on with the teacher standing next to you.

In the meantime, for a lot more in the way of books, instruction, etc., take a look at this site:

http://www.tubebooks.org/technical_books_online.htm

Scroll about 3/4 of the way down until you get to the section labeled: "Test & Measurement (equipment & instructions)", and you'll find several books on oscilloscope usage.

Enjoy the journey!:thmbsp:

 

[Steelman]

Ok, so you're getting to the real issue. I'd strongly suggest you pick up some basic electronics books and work through them. This will take some electronics parts, a breadboard and a power supply. When you start getting into AC signals, then you'll be able to pull out the scope and start understanding how to set it up to view the waveforms your theory tells you should be there.

This will, then, bring you the insight you seek - I hope!

Cheers,

David

I fear the books will again frustrate me. Not the books per say...but my inability to comprehend them without the basics.

 

[Steelman]

Relax-you'll learn it!
Basically:
The vertical is for the "amplitude"=voltage.
The horizontal is for the "period"=frequency.
Volts/div. and time/div. are for actually measuring the voltage and frequency, using the grids and lines on the screen.
Triggering is for obtaining a stable display (not moving).
Focus, trace rot., etc. are for obtaining a clear trace.
I'd also recommend Tektronix's XYZ's of Using A Scope-ironically I obtained one recently cuz I couldn't remember how to use the B Delayed by A function.
Learn your electronics in steps-from the beginning.
I'll bet a local Amateur Radio Club or member would gladly help you.
Good Luck! We all started at the beginning!

Thanks for the wish of luck and your reply :thmbsp:
I'll need it :sigh:

 

[Steelman]

I'm afraid I don't understand what you're trying to say, but given that the OP is a beginner I have to strongly suggest that he not pay attention to your post since your post is incorrect. Reversing the probe connections will do far more than simply "turning the sine wave upside down". Following your statement can cause catastrophic damage to equipment connected to an oscilloscope.

The proper use of the probe and ground clip does matter, and in fact failing to understand circuit grounds and earth grounds and how an oscilloscope works with grounds is probably the single most serious mistake a beginner can make, along with connecting to a voltage source higher than the scope can handle.

If you have a scope probe connected properly, with the ground clip connected to circuit ground and the main probe connected to the point in the circuit where you wish to measure a voltage and/or observe a waveform, and then you reverse the connections, you will take the point in the circuit where you were taking measurements and make a dead short connection from that point to ground, possibly destroying multiple components in the process.

To Steelman:

First, congrats on wanting to learn new things!! This electronics stuff really is fascinating, and you will find it increasingly interesting the deeper you get into it. Unfortunately, as you're already finding out, learning it all by yourself can be both frustrating as well as compelling. I would strongly urge you to take another look at your local community/junior college Electronics Technology offerings. No, you won't find a course on "Using an Oscilloscope", any more than you will find a class on "Using a Socket Wrench" listed under Automotive Technology. You'll learn how to use the tools when you take a class on how to work on engines. If you take an Introduction to Electronics course, then the next two classes you would normally take are DC Circuits and AC circuits. In those classes, particularly AC Circuits, you'll get to play with scopes for hours on end, and you'll learn a lot. Nothing beats hands-on with the teacher standing next to you.

In the meantime, for a lot more in the way of books, instruction, etc., take a look at this site:

http://www.tubebooks.org/technical_books_online.htm

Scroll about 3/4 of the way down until you get to the section labeled: "Test & Measurement (equipment & instructions)", and you'll find several books on oscilloscope usage.

Enjoy the journey!:thmbsp:

Thanks...It seems the older I get, the more I want to expand my knowledge base and skill set. I wish I had this thirst and drive when I was in school...

...nothing beats hands on with the teacher standing next to you...

I couldn't agree more.

Sure hope I can find a teacher for this old dog to learn a few new tricks.

Thanks for clearing up some confusing opinions :thmbsp:

Vincent

 

[Fisherdude]

I fear the books will again frustrate me. Not the books per say...but my inability to comprehend them without the basics.

Vincent, this is the core issue that is causing you so much frustration. You won't be able to comprehend a book about oscilloscopes if you don't already have an understanding of basic electronics principles. Don't misunderstand, you certainly don't have to be an expert by any means, but an oscilloscope is not an instrument that you can get much use from if you don't have a reasonable understanding of basic electronics. An oscilloscope will allow you to test A, B, and C. Well, if you don't know what A, B, and C mean, how can you understand how to test and measure them, and what it means if A is too high and C is too low?

The problems with books is that it's very, very difficult to understand what's in the book if you can't set it down, turn to a real piece of simple circuitry, and puzzle it through. Ohm's Law won't begin to really make sense until you have a simple circuit on a protoboard, and when you turn the potentiometer back and forth you can see current go up and down. If you can't take a class at the local community college, I would suggest that you start with a book on basic electronics first. There are hundreds of them. You can find them at the local Barnes & Noble, or Amazon, or your library.

When you get stuck, just ask a question! There are plenty of us here who are more than willing to help, if you're at least willing to try!:yes:

 

[Steelman]

Vincent, this is the core issue that is causing you so much frustration. You won't be able to comprehend a book about oscilloscopes if you don't already have an understanding of basic electronics principles. Don't misunderstand, you certainly don't have to be an expert by any means, but an oscilloscope is not an instrument that you can get much use from if you don't have a reasonable understanding of basic electronics. An oscilloscope will allow you to test A, B, and C. Well, if you don't know what A, B, and C mean, how can you understand how to test and measure them, and what it means if A is too high and C is too low?

The problems with books is that it's very, very difficult to understand what's in the book if you can't set it down, turn to a real piece of simple circuitry, and puzzle it through. Ohm's Law won't begin to really make sense until you have a simple circuit on a protoboard, and when you turn the potentiometer back and forth you can see current go up and down. If you can't take a class at the local community college, I would suggest that you start with a book on basic electronics first. There are hundreds of them. You can find them at the local Barnes & Noble, or Amazon, or your library.

When you get stuck, just ask a question! There are plenty of us here who are more than willing to help, if you're at least willing to try!:yes:

I think I will revisit Kingsboro or Brooklyn college and talk to someone rather than try to find a course on my own.

Thanks very much for the encouragement :thmbsp:

Vincent

 

[Fisherdude]

You betcha! Keep at it!

 

[Hyperion]

If I'm understanding this correctly, I don't recommend this at all.
If you reverse the scope ground and the scope probe connection (Ground connected to amp output), the computer ground and the scope ground will be commoned. Your amp will dislike you.

Also, if the grounds were not common, the signal will not be turned "upside down", unless you trigger from the signal generator. If your triggering from the waveform itself, it will be edge triggered, triggered by a positive going edge or a negative going edge. Inverting a sine wave input will show no difference as far as the scope's display is concerned.

My oscilloscope has a front panel switch that causes the trace to be inverted - this is done electronically within the oscilloscope, and has nothing to do with the very dangerous suggestion of reversing the positions of the tip and ground clip of the probe.

Just thought I would mention that.

To Steelman - I wish you the very best of luck in your endeavours :thmbsp:

 

[Steelman]

My oscilloscope has a front panel switch that causes the trace to be inverted - this is done electronically within the oscilloscope, and has nothing to do with the very dangerous suggestion of reversing the positions of the tip and ground clip of the probe.

Just thought I would mention that.

To Steelman - I wish you the very best of luck in your endeavours :thmbsp:

Thanks John :thmbsp:

 

[Slash5]

I was in the same boat as you - and not much advanced beyond that yet.
I found this site got me started:
http://www.doctronics.co.uk/scope.htm
No theory, just things to do.

Then I hooked the oscilloscope up to the negative and positive speaker terminals of a little amp, turned the volume up just a little, and fed an input in from my computer sound card using Audacity to generate a tone. I played with buttons and knobs until I had a clue what was going on.
Need to do some more reading now that I know a little.

 

[oiseaux]

Steelman, the safest, smartest thing for you to do is find the nearest community college and sign up for Basic Electronics 101. You will have much fun, get your questions answered, and not electrocute yourself in your desire for knowledge.
Most here have wonderful suggestions but you are getting pennies and nickels of knowledge to spend when you need a savings account to build upon.
Cheers!

 

[Steelman]

I was in the same boat as you - and not much advanced beyond that yet.
I found this site got me started:
http://www.doctronics.co.uk/scope.htm
No theory, just things to do.

Then I hooked the oscilloscope up to the negative and positive speaker terminals of a little amp, turned the volume up just a little, and fed an input in from my computer sound card using Audacity to generate a tone. I played with buttons and knobs until I had a clue what was going on.
Need to do some more reading now that I know a little.

Thanks for the advise and the link :thmbsp:

 

[Steelman]

Steelman, the safest, smartest thing for you to do is find the nearest community college and sign up for Basic Electronics 101. You will have much fun, get your questions answered, and not electrocute yourself in your desire for knowledge.
Most here have wonderful suggestions but you are getting pennies and nickels of knowledge to spend when you need a savings account to build upon.
Cheers!

:thmbsp:

 

[HiFiCanada]

Extra info

Heathkit had some good tutoral manuals on using your scope, sometimes available on E-bay, I have seen one not to long ago.
I have added a picture of frequency generator and some info on Sine and Square waves.

 

[jleon92f]

Also, do you have a freguency/function generator? You will need one of these for you to be able to utilize a scope.

I am also trying to learn how to use my O scope, what kind of FG should I get?

Thanks,
John.

 

[jleon92f]

Hi, Can you use a actual audio source like a tape deck as your input audio source?

Thanks,
John.

 

[Steelman]

Heathkit had some good tutoral manuals on using your scope, sometimes available on E-bay, I have seen one not to long ago.
I have added a picture of frequency generator and some info on Sine and Square waves.

That info on sine wave distortion is just the type of info that can help me decipher what is being displayed on the scope.

Thank you very much!

Vincent

 

[Steelman]

First off, I would like to thank everyone who has encouraged me to learn how to use (this very elusive to me) piece of equipment. Thanks to all who provided links, opinions and experience.

Well, I have spent the last three hours sending a sine wave from my laptop (using sweepgen 3.5.2...all I have at the moment for a signal generator) to the scope. I was able to see the sine wave on the BK 2120B perfectly...

I then sent the signal from the laptop to a receiver I know is working through the AUX input and then to the scope. Both sine waves were equal and distortion free...so far so good.

I then sent the signal through a junker unit I know has a problem with one channel. Not only was I not able to focus in on a undistorted sine wave, I was unable to find anything that could remotely resemble a sine wave...

Now, all I have to do is learn how to trouble shoot the junker with the scope.....I hope I have enough years left, I'm not getting any younger

 

[jleon92f]

First off, I would like to thank everyone who has encouraged me to learn how to use (this very elusive to me) piece of equipment. Thanks to all who provided links, opinions and experience.

Well, I have spent the last three hours sending a sine wave from my laptop (using sweepgen 3.5.2...all I have at the moment for a signal generator) to the scope. I was able to see the sine wave on the BK 2120B perfectly...

I then sent the signal from the laptop to a receiver I know is working through the AUX input and then to the scope. Both sine waves were equal and distortion free...so far so good.

I then sent the signal through a junker unit I know has a problem with one channel. Not only was I not able to focus in on a undistorted sine wave, I was unable to find anything that could remotely resemble a sine wave...

Now, all I have to do is learn how to trouble shoot the junker with the scope.....I hope I have enough years left, I'm not getting any younger

Very cool way to do things, hang in there I have been trying this for he last 4 years or so..Make it fun it helps. I have a receiver on my bench now that has a weak Left channel..I get a lot of these, one channel works and the other one is weak.

Thanks,
John.

 

[HiFiCanada]

Very handy tool to check some components, like audio caps, besides using the VTM, put a square wave or sine wave through a cap and see if it is distorted or not. Have fun with it and play around with it to get the hands on experence you need, but stay away from the high voltage stuff for now.
Note: Discharge the larger electrolic caps used in power supplies, before doing any tests.
Read up on you manuals and get to know the scope very well and really understand the grounding method and safety precautions you need to use to test amplifiers and receivers that have to be tested with the power on.